Seismic scaling relation of the 2007 Off Mid Niigata, Japan, earthquake (Mw 6.6) sequence in comparison with two other earthquake (Mw 6.6) sequences

AbstractThe relationship of seismic moment (M0) to corner frequency (fc) of the 2007 Off Mid Niigata prefecture (Chuetsu-oki) earthquake sequence is examined in comparison with that of two other earthquake sequences. TheM0-f0relation of this sequence (3.4 ≤Mw≤ 6.6) isM0∝fc−3.87, which deviates fromM0∝fc−3. The relatively large deviation fromfc−3may reflect the influence of fluids identified in tomographic studies around the source region of the tectonic strain concentration. Moreover, the lowerfcs of the small events (3.4 ≤Mw≤ 3.8) in this sequence are similar to those of off-main-fault events in the 2004 Mid Niigata prefecture earthquake sequence. The characteristics in the scaling relation may be interpreted in the context of the event locations, which are either on- or off-main faults, and may have implications for the seismogenic conditions. Key words: The 2007 Off Mid Niigata earthquake, seismic scaling, seismogenic conditions.